House Intelligence Committee Chairman Devin Nunes, R-Calif., said Sunday there is now "absolute proof" that the FBI failed to inform the Foreign Intelligence Surveillance Court of pertinent Democratic interests when applying to spy on onetime Trump campaign official Carter Page.

The ex-top lawyer at the FBI, James Baker, told congressional investigators last week in a closed session that a Democrat-connected attorney from the law firm linked to the controversial Trump dossier gave him materials about Russian election meddling to the FBI's general counsel during the 2016 presidential campaign.

During an appearance on Fox News, Nunes said this revelation is important because Baker reported directly to former FBI Director James Comey and because it clashed with sworn testimony by federal officials.

"Numerous officials at the DOJ and the FBI have told us under oath ... nobody at FBI or DOJ knew anything about that the Democratic Party being behind the Clinton dirt," Nunes said. "Now you have one of the top lawyers for the Democrats and the Clinton campaign who was feeding information directly to the top lawyer at the FBI."

"Before even the FISA warrant," he continued. "Now you have absolute proof that that wasn't told to the FISA court. So you want your the evidence of FISA abuse? There it is right there."

Baker was a key player in successfully obtaining multiple warrants for Page. According to a Daily Caller report, Baker, who served as the FBI's top lawyer until May, told Congress on Wednesday that Michael Sussmann, of Perkins Coie, passed on documents to him about Russian efforts to influence the 2016 election. Baker said he did not read all the information provided by Sussmann, but described the meeting as "atypical."

President Trump and his GOP allies in Congress have condemned the FBI for relying in part on the Trump dossier, compiled by former British intelligence officer Christopher Steele, to gain authority to gather information about Page, a U.S. citizen on American soil who had suspicious ties to Russia. The dossier, which includes unsubstantiated, controversial claims about Trump and prostitutes in a Moscow hotel room, was commissioned by opposition research firm Fusion GPS.

Republicans have accused the FBI of misleading the FISA court by exempting from the Page warrants clear indication that the dossier was partly financed by the Democratic National Committee and Hillary Clinton's campaign via the Perkins Coie law firm.

Nunes said this testimony from Baker, which his GOP colleague Rep. Mark Meadows called "explosive," reinforces the need for Trump to declassify Russia-related documents as it proves Democrats, not Republicans are behind misconduct in the FBI and DOJ.

"If he does not declassify it, he's going to let these criminals -- this criminal activity and fraudulent behavior -- people are going away with it if this information is not declassified so that all of the American people can see," Nunes said. Democrats have said the push to declassify the documents would endanger national security by revealing sources and methods the intelligence community uses to attain information and accused Republicans of trying to taint the federal Russia investigation.

After making a declaration last month to have these documents declassified and Russia-related texts from officials, including FBI Director James Comey, released, Trump reversed course days later, announcing after meeting with DOJ officials warning that the move could be perceived as tampering with the Russia investigation and hearing concerns from "key allies," that he would leave it to the DOJ inspector general to review the documents.

Nunes is skeptical of this sudden change of heart, noting that Deputy Attorney General Rod Rosenstein, who is overseeing special counsel Robert Mueller's Russia investigation, was a part of that meeting -- the same people, he said, who were involved in the FISA warrant process.

"You cannot buy any of this from these guys," he said.